Water Delivery System For Upper Spray Arm Of A Dishwasher

ABSTRACT

A dishwasher has an upper rack that carries a spray arm having a horizontal manifold tube that engages in a port associated with a vertical main feed tube for supplying wash water to the spray arm. There can be from one to a plurality of ports into which the manifold tube can be inserted. A check valve assembly can be included when there are a plurality of ports, the check valve assembly having from one to a plurality of flapper valves for closing each port when the manifold tube is withdrawn. The manifold tube has an entrance region at its open end that engages the/each port. The entrance region has a mouth lying in a plane oblique to the vertical and horizontal directions.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of the filing date of U.S. Provisional Patent Application Ser. No. 60/916,124 filed on May 4, 2007, the entire disclosure of which is hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present disclosure relates generally to automatic dishwashers, and more particularly to dishwashers that have an upper rack that slides in and out of the dishwasher to facilitate loading and unloading of the rack, and in which a spray arm is connected to the rack such that it moves inwardly and outwardly with the rack. The upper rack can be either at a fixed height or can be adjustable between a plurality of positions differing in height.

In dishwashers of this type, the spray arm attached to the upper rack receives wash water from the pump of the dishwasher via a delivery system that includes a wash water feed tube typically extending vertically adjacent the rear wall of the tub, and a manifold tube that is attached to the upper rack. In dishwashers having a fixed-height upper rack, when the upper rack is slid all the way into the dishwasher the end of the manifold tube is inserted into a port connected to the feed tube, thereby fluidly connecting the manifold tube to the feed tube. In dishwashers having an adjustable-height upper rack, there are a plurality of vertically spaced ports, and the manifold tube can be inserted into any of the ports, depending on the height position of the upper rack. The insertion of the manifold tube into one of the ports opens the check valve for that port, so as to allow wash water to flow from the feed tube into the manifold tube for the spray arm. Each port not being used is closed by a valve member of the check valve assembly. When the manifold tube is withdrawn from the active port upon sliding the upper rack out of the dishwasher, the associated valve member closes the port. The rack can then be slid back into the dishwasher in the same vertical position, or the rack can first be adjusted to a different vertical position and then slid back in such that the manifold tube is inserted into a different one of the ports.

A wide variety of valve and manifold tube arrangements have been developed or proposed for such dishwashers. The present disclosure relates to improvements in such valve and manifold tube arrangements.

BRIEF SUMMARY OF THE DISCLOSURE

The present disclosure concerns a wash water delivery system for a spray arm of a dishwasher. In accordance with one aspect of the present disclosure, the wash water delivery system comprises a main feed tube for supplying wash water for the spray arm. The main feed tube extends along a generally vertical direction when installed in a dishwasher. A port is defined either in the main feed tube itself or in another member connected with the main feed tube, wash water being delivered from the main feed tube through the port for supply to the spray arm. The system further comprises a manifold tube for the spray arm, the manifold tube having an open end for insertion into the port.

The manifold tube extends along a generally horizontal direction that is generally perpendicular to the generally vertical direction, and the open end of the manifold tube has an entrance region for capturing wash water flowing in the main feed tube along the generally vertical direction and turning the wash water to flow along the generally horizontal direction. The entrance region has a mouth lying substantially in a plane that is oriented obliquely to the generally horizontal direction and obliquely to the generally vertical direction.

In one embodiment, the entrance region of the manifold tube has an upper wall formed substantially as a ramp that is inclined relative to the generally horizontal direction. The upper wall can have an inner surface that is substantially planar over a predetermined distance in a flow direction and over a predetermined distance in a transverse direction perpendicular to the flow direction.

When employed in a dishwasher having a height-adjustable upper rack, the main feed tube defines a plurality of vertically spaced apertures, and the assembly comprises a check valve assembly defining a separate port for each of the apertures in the main feed tube. The check valve assembly includes a plurality of valve members respectively arranged to close each of the ports when the open end of the manifold tube is withdrawn from the port, each valve member being pushed open when the open end of the manifold tube is inserted into the respective port.

The check valve assembly can comprise (i) a front cover of relatively hard and rigid material releasably attached to the main feed tube, the front cover defining from one to a plurality of generally cylindrical passages respectively aligned with the aperture(s) in the main feed tube, each passage extending generally parallel to the generally horizontal direction and having a front end spaced relatively far from the main feed tube and a rear end spaced relatively closer to the main feed tube; (ii) from one to a plurality of generally annular valve seats of relatively softer, less rigid material than the front cover and respectively attached to the front end(s) of the passage(s), each valve seat defining a central hole of smaller diameter than an inner surface of the corresponding passage in the front cover; and (iii) a valve body of relatively softer, less rigid material than the front cover disposed between the main feed tube and the front cover. The valve body defines from one to a plurality of orifices in respective sealing engagement with the passage(s) of the front cover and with the aperture(s) in the main feed tube, the valve body further comprising a flapper valve for the/each orifice. The/each flapper valve is pivotally connected to the valve body so as to be pivotal between a closed position engaging the respective valve seat and an open position spaced from the valve seat. In the closed position, the/each flapper valve resides intermediate the front end and the rear end of the respective passage of the front cover. This arrangement gives the check valve assembly a relatively low profile such that it extends into the interior of the dishwasher a relatively small distance.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Having thus described the disclosure in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

FIG. 1 is a perspective view, partly broken away, of a dishwasher in accordance with one embodiment of the invention;

FIG. 2 is a perspective sectioned view of a wash water delivery system and spray arm in accordance with one embodiment of the invention;

FIG. 3 is a cross-sectional view of the check valve assembly;

FIG. 4 is a perspective sectioned view of the open end of a manifold tube of a wash water delivery system in accordance with one embodiment of the invention; and

FIG. 5 is an exploded view of the check valve assembly.

DETAILED DESCRIPTION OF THE DRAWINGS

The present invention now will be described more fully hereinafter with reference to the accompanying drawings in which some but not all embodiments of the inventions are shown. Indeed, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.

FIG. 1 shows a dishwasher 10 having a wash water delivery system in accordance with one embodiment of the invention. The dishwasher includes a tub 12 (partly broken away in FIG. 1 to show internal details) forming an enclosure in which dishes and utensils are placed for washing. The tub includes a door 13 that can be opened to access the interior of the tub. As well known in the art, the dishwasher includes a bottom rack and an upper rack (omitted from the drawings for clarity) for holding the dishes and utensils, and each of the racks is mounted to slide inwardly and outwardly through the open door to facilitate loading and unloading of dishes and utensils. The tub also defines a sump (shown generally at 14 in FIG. 1) in which wash water or rinse water is collected. The water is pumped by a pump 15 from the sump to various spray arms mounted in the interior of the tub for spraying the water under pressure onto the dishes and utensils. The spray arms are rotatable for ensuring that all areas in the interior of the tub are exposed to the water discharged from the spray arms.

The upper rack can be adjustable to different vertical positions. This allows the user to lower the rack when inordinately tall items are to be placed in the upper rack, or to raise the rack when more vertical space is needed for items in the lower rack. In the illustrated embodiment, the upper rack has three different positions that can be selected. However, the present invention is not limited to height-adjustable racks, but can also apply to fixed-height racks.

The spray arms typically include an uppermost spray arm (not shown) mounted to an underside of an upper wall of the tub 12 for spraying water generally downwardly, and a lowermost spray arm 18 mounted on an upper side of a bottom wall of the tub for spraying water generally upwardly. The spray arms also include a mid-level spray arm 20 that is attached to an underside of the upper rack and is configured for spraying water both upwardly and downwardly. The spray arm 20 is supplied with water via a manifold tube 22 that extends generally horizontally along the underside of the upper rack. As will be appreciated, when the upper rack is adjusted to different vertical positions, the manifold tube 22 moves with the upper rack and thus also assumes different vertical positions.

The water delivery system for the spray arm 20 includes a main feed tube 24 that connects to the pump 15 at the lower end of the conduit, extends generally vertically upwardly adjacent a rear wall of the tub 12, and then turns to extend generally horizontally along the underside of the upper wall of the tub for supplying water to the uppermost spray arm. Along the generally vertical portion of the main feed tube is a check valve assembly 30 that cooperates with the manifold tube 22 to supply water to the mid-level spray arm 20. The check valve assembly 30 allows the manifold tube 22 to be fluidly coupled with the main feed tube 24 when the upper rack is slid all the way into the interior of the tub 12, and to be disconnected from the main feed tube when the upper rack is slid out for loading or unloading dishes and utensils.

The wash water delivery system for the spray arm 20 is shown in detail in FIGS. 2 through 5. The system includes the manifold tube 22, the main feed tube 24, and the check valve assembly 30. The main feed tube 24 comprises a tubular structure having a cross-sectional shape that is generally rectangular, with the dimension in the front-to-back direction of the dishwasher being substantially smaller than the dimension in the side-to-side direction. The main feed tube thus is generally flattened so that it has a low profile on the rear wall of the tub. The main feed tube has a front wall 26 in which a plurality of apertures 28 are formed. The apertures 28 are spaced apart along the generally vertical direction in which the conduit extends. Each side edge of the main feed tube defines a plurality of vertically spaced protuberances or catches 25. A raised annular boss 29 surrounds each aperture 28 and projects in the forward direction (i.e., toward the door 13 (FIG. 1) of the dishwasher. Each boss 29 has a tapered or generally conical configuration such that the boss decreases in diameter in the forward direction.

The check valve assembly 30 comprises a front cover 40 and a valve body 60. The front cover 40 comprises a molded plastic structure that is relatively hard and rigid in comparison with the valve body 60. The front cover has a front wall 42, a top wall 43 joined to a top edge of the front wall and extending rearwardly therefrom, and a pair of spaced side walls 44 (FIG. 5, only one side wall 44 being visible) joined respectively to the opposite side edges of the front wall and extending rearwardly therefrom generally parallel to each other. Each side wall 44 defines recesses or apertures 45 that receive the catches 25 on the main feed tube in a snap-fit fashion, such that the front cover 40 can be secured to the main feed tube in snap-fit fashion. The top wall 43 of the front cover also defines a tab 46 that is received in a recess 47 defined in the front wall 26 of the main feed tube when the front cover is snapped into place on the conduit, for further stabilizing the connection between the front cover and main feed tube. The front cover 40 further defines a plurality of hollow generally cylindrical tubes 48 spaced apart along the generally vertical direction, the tubes thus forming generally cylindrical passages through the front cover. Each of the tubes 48 is aligned with a corresponding one of the apertures 28 in the main feed tube 24 when the front cover is snapped onto the conduit. Each tube 48 penetrates through the front wall 42 of the front cover and thus has a front end that extends slightly forward of the front wall. A rear end of each tube 48 is spaced slightly from the front wall 26 of the main feed tube 24 and the inner diameter of the tube is larger than that of the raised boss 29 surrounding the respective aperture 28 in the main feed tube.

The front cover 40 also includes a plurality of generally annular valve seats 50 of relatively softer, less rigid material than the front cover and respectively attached to the front ends of the tubes 48. The valve seats each defines a central hole of smaller diameter than the inner diameter of the corresponding tube 48. As illustrated, the valve seats advantageously have a tapered or generally conical configuration such that they decrease in diameter in the rearward direction toward the main feed tube 24. The valve seats 50 can comprise an elastomeric material such as silicone rubber or the like. The valve seats can be formed separately and then secured to the front cover, or alternatively the valve seats can be overmolded on the front cover. The overmolding process is well known and thus is not described further herein. The central hole in each valve seat 50 has a diameter slightly smaller than the outside diameter of the end portion of the manifold tube 22 such that a substantially sealed interface is formed between the manifold tube and the valve seat when the end of the manifold tube is inserted into the central hole of the valve seat.

The valve body 60 comprises a one-piece molded polymer structure that is of relatively softer, less rigid material than the front cover. The valve body is disposed between the main feed tube 24 and the front cover 40. The valve body defines a plurality of separate orifices 62 spaced apart along the generally vertical direction. Each orifice is defined by a short generally cylindrical protrusion 64 that extends in the forward direction from a generally planar portion 66 of the valve body. Each generally cylindrical protrusion 64 has an outer diameter that fits closely into the respective tube 48 of the front cover 40, and the rear ends of the tubes 48 abut the generally planar portion 66 of the valve body, such that a generally sealed interface exists between the tubes 48 and the protrusions 64 of the valve body. The generally planar portion 66 of the valve body is slightly compressed between the rear ends of the tubes 48 and the front wall 26 of the main feed tube 24, thereby providing a substantially sealed connection between the main feed tube 24, the valve body 60, and the front cover 40. Accordingly, wash water in the main feed tube is in fluid communication with the tubes 48 via the orifices 62 in the valve body 60.

The valve body 60 also includes a flapper valve 68 for each orifice 62. Each flapper valve is pivotally connected to the valve body so as to be pivotal between a closed position (shown for the uppermost and lowermost flapper valves in FIG. 3) engaging the respective valve seat 50 of the front cover, and an open position (shown for the middle flapper valve in FIG. 3) spaced from the valve seat 50. Each flapper valve in the closed position resides intermediate the front end and the rear end of the respective tube 48 of the front cover. In the illustrated embodiment, each flapper valve 68 is connected to the end of an arm 70 that is attached to the respective cylindrical protrusion 64 at its upper side. Each arm extends in the forward direction from the protrusion toward the respective valve seat 50 and then bends about 90° and extends a short distance downwardly and terminates at its connection to the flapper valve 68. The flapper valves 68 thus hang downwardly, and pivot about horizontal axes at their connections to the arms 70 when moved between the closed and open positions. Because the flapper valves hang downwardly from their pivot axes, gravity tends to assist the “memory” of the material in moving the flapper valves toward their closed positions.

To establish a connection between the spray arm manifold tube 22 and the main feed tube 24, the end portion of the manifold tube 22 is inserted into one of the ports defined by the check valve assembly 30, i.e., into the central hole defined by the valve seat 50. The end of the manifold tube thus pushes the flapper valve 68 to its open position, as shown for the middle port in FIG. 3. The other ports remain closed by the flapper valves 68, which are urged by water pressure against the valve seats 50 so that substantially no leakage of water occurs through the closed ports. The end of the manifold tube 22 abuts or is closely adjacent to the rear wall 27 of the main feed tube. Wash water thus can flow upwardly within the main feed tube 24 and enter the end of the manifold tube 22, where the water is then turned about 90° (i.e., from the generally vertical direction to the generally horizontal direction along which the manifold tube extends) to flow through the manifold tube 22 to the spray arm 20. The check valve assembly 30 thus allows a substantially sealed connection to be established between the manifold tube and the main feed tube in any of the plurality (three, in the illustrated embodiment) of vertical positions of the manifold tube corresponding to the various vertical positions of the upper rack to which the manifold tube is connected.

Wash water flowing in the main feed tube 24 must be turned through an angle of substantially 90° to flow through the manifold tube 22, as previously noted. Whenever fluid is turned through a substantial angle over a short distance, pressure losses tend to be significantly increased, but the losses can be minimized or reduced by careful shaping of the flow passage. It is desirable to minimize the total pressure loss resulting from the capturing of the wash water by the manifold tube and the 90° turning of the water. In accordance with the present invention, the end portion of the manifold tube is shaped in a particular manner for facilitating relatively efficient capturing and turning of the water. More particularly, with reference to FIGS. 3 and 4, the end of the manifold tube 22 is configured to have a mouth that lies substantially in a plane 80 that is oriented obliquely to both the vertical direction along which the main feed tube 24 extends and the horizontal direction along which the manifold tube 22 extends. In the illustrated embodiment, the plane 80 of the mouth forms an angle of approximately 45° with respect to both the vertical and horizontal directions. The end of the manifold tube includes an upper wall 82 that extends farther in the rearward direction (toward the rear wall 27 of the main feed tube 24) than does the lower wall 84 of the manifold tube.

The upper wall 82 thus forms an “overhang” against which wash water flowing upwardly in the main feed tube impinges. The upper wall 82 essentially comprises a ramp that is inclined with respect to the horizontal direction. The inner surface of the upper wall 82 (i.e., the surface against which the upwardly flowing water impinges) is substantially planar over a predetermined distance along the flow direction (i.e., generally right-to-left in FIG. 3), and over a predetermined distance in the transverse direction (i.e., perpendicular to the plane of FIG. 3). The rear edge of the upper wall 82 thus is substantially linear over the predetermined distance in the transverse direction, as best seen in FIG. 4, and therefore when this edge abuts the rear wall 27 of the main feed tube it substantially prevents water from flowing between the edge and the rear wall (although water can still flow around the sides of the manifold tube and, indeed, the entire space bounded between the rear wall of the conduit and the tubes 48 and flapper valves 68 and valve seats 50 is substantially filled with water when the pump is operating and water is flowing into the manifold tube 22). This facilitates capturing of the water by the mouth of the manifold tube 22. The upper wall 82 at its forward and side edges joins with the generally tubular inner surface of the main portion of the manifold tube, and the junctions therebetween are faired so that sharp corners are avoided. In this manner, water captured in the mouth of the manifold tube is turned by the upper wall 82 to flow in the manifold tube to the spray arm.

In operation, a user adjusts the upper rack of the dishwasher to the desired vertical position, which thus positions the manifold tube 22 in alignment with either the top port, the middle port, or the bottom port of the check valve assembly. Once the upper rack has been loaded with dishes and utensils to be cleaned, the upper rack is slid into the dishwasher, which causes the end of the manifold tube 22 to be inserted into the port corresponding to the rack position. The flapper valve 68 for that port is opened by the end of the manifold tube. The valve seat 50 substantially seals around the outside of the manifold tube. Additionally, the valve body 60 substantially seals the interface between the raised bosses 29 of the main feed tube and the tubes 48 of the front cover 40. Accordingly, water is substantially prevented from leaking from the main feed tube into the interior of the dishwasher tub, and instead at least part of the water is substantially constrained to flow into the manifold tube 22 to the mid-level spray arm 20. When there is a top spray arm, another portion of the water in the main feed tube flows around the manifold tube and is supplied to the top spray arm.

The wash water delivery system described and illustrated herein has a number of advantages or useful features relative to prior systems. In particular, the shaping of the entrance region of the manifold tube 22 facilitates delivery of water to the spray arm 20 with reduced loss of pressure caused by the capturing and turning of the water by the manifold tube.

Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. For example, as noted, the invention is applicable not only to dishwashers having height-adjustable upper racks, but also to dishwashers having fixed-height upper racks. In that case, the check valve assembly is omitted, and the manifold tube simply extends into a port associated with the main feed tube when the upper rack is slid into the dishwasher. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. 

1. A wash water delivery system for a spray arm in a dishwasher, comprising: a main feed tube for supplying wash water for the spray arm, the main feed tube extending along a generally vertical direction when installed in a dishwasher; a port in fluid communication with the main feed tube, wash water being delivered from the main feed tube through the port for supply to the spray arm; and a manifold tube for the spray arm, the manifold tube having an open end for insertion into the port so as to fluidly connect the manifold tube to the main feed tube; wherein the manifold tube extends along a generally horizontal direction that is generally perpendicular to the generally vertical direction, and the open end of the manifold tube has an entrance region for capturing wash water flowing in the main feed tube along the generally vertical direction and turning the wash water to flow along the generally horizontal direction, the entrance region having a mouth lying substantially in a plane that is oriented obliquely to the generally horizontal direction and obliquely to the generally vertical direction.
 2. The wash water delivery system of claim 1, wherein the entrance region of the manifold tube has an upper wall formed substantially as a ramp inclined relative to the generally horizontal direction.
 3. The wash water delivery system of claim 2, wherein the upper wall has an inner surface that is substantially planar over a predetermined distance in a flow direction and over a predetermined distance in a transverse direction perpendicular to said flow direction.
 4. The wash water delivery system of claim 1, wherein there are a plurality of vertically spaced ports in fluid communication with the main feed tube, and the system further comprises a check valve assembly including a plurality of valve members respectively arranged to close each port when the open end of the manifold tube is withdrawn therefrom, each valve member being pushed open when the open end of the manifold tube is inserted into the respective port. 